1. Field of the Invention
The present invention relates to an optical imaging lens assembly, and more particularly to the optical imaging lens assembly to shorten total length and lower cost for applying to electronic products.
2. Description of the Related Art
In compact electronic products such as digital still cameras or mobile phone cameras, an optical imaging lens assembly is generally installed for capturing images of an object, and the optical imaging lens assembly tends to be developed with a compact design and a low cost, while meeting the user requirements of good aberration correction ability, high resolution, and high image quality.
In general, a conventional optical imaging lens assembly of a compact electronic product comes with different designs, including the two-lens, three-lens, four-lens, and five-or-more lens designs. However, if the imaging quality is taken into consideration, the optical imaging lens assembly with the four-lens or five-lens designs has advantages on image aberration and modulation transfer function (MTF) performance, wherein the five-lens design having a higher resolution than the four-lens designs thus being applicable for electronic products requiring the high quality and high pixels.
In various compact designs of the five-lens optical imaging lens assembly having a fixed focal length, prior arts adopt different combinations of positive and negative refractive powers and a group of stacked lens elements as disclosed in publications and U.S. Pat. Nos. US2004/0196571 and US2003/0117722, or the first lens element with negative refractive power for reducing the total length of the optical system as disclosed in U.S. Pat. No. 7,480,105.
In products such as compact digital cameras, web cameras, and mobile phone cameras, the optical imaging lens assembly requires a compact design, a short focal length, and a good aberration correction. In various different five-lens designs for an optical imaging lens assembly with a fixed focal length, it is relatively difficult for a combination of the fourth lens element and the fifth lens element with different refractive powers, and the fourth lens element or the fifth lens element having an inflection point to achieve a good aberration correction and meet the design requirement for the total length of the optical imaging lens assembly. As disclosed in U.S. Pat. No. 7,710,665, a good aberration correction can be achieved, but the total length of the optical imaging lens assembly still fails to meet the requirements to satisfy the specifications for compact electronic device. As disclosed in publications and U.S. Pat. No. 7,826,151, US2010/0254029, US2010/0253829, the fourth lens element and the fifth lens element having an inflection point respectively are used for designing a shorter total length. As disclosed in publications and U.S. Pat. Nos. 7,826,151, 7,502,181, and US2010/0134904, a combination of the first lens element with positive refractive power, the second lens element with negative refractive power and the third lens element with positive refractive power are used to achieve a higher image capturing ability. Among these prior arts, the fourth lens element or fifth lens element having an inflection point can correct aberration or distortion, but a longer distance between the third lens element and the fourth lens element is required, which is unfavorable to the design of a shorter total length.
Therefore, the present invention provides a more practical design to shorten the optical imaging lens assembly, while using a combination of refractive powers and a combination of convex and concave surfaces of five lens elements to reduce the total length of the optical imaging lens assembly and improve the image quality, so that the optical imaging lens assembly can be applied to compact electronic products.